Radio control system and multiple circuit switch



April 11, 1944. E. F. MCD N JR 2,346,177

RADIO CONTROL SYSTEM AND MULTIPLE CIRCUIT SWITCH Filed April 25, 1941 2 Sheets-Sheet l INVENTOR E use/v5 E Mafia/mm, JR.

Mimi.

ATTORNEYb April 1944. E. F. M DONALD, JR ,3 6,

RADIO CONTROL SYSTEM AND MULTIPLE CIRCUIT SWITCH Filed April 25, 1941 2 Sheets-Sheet 2 4 7 m B 5/ 2 4 l 3 7 I 6 E 6 8 B m E W =:R 3 F 9 B. B 9 I 2 w 5 m 2 9\ w I 4 8 6 I m 8 8 B M M m+7tom ATTORNEYS W 2 m m k a m Patented Apr. 11, 1944 RADIO CONTROL SYSTEM AND MULTIPLE CIRCUIT SWITCH Eugene F. McDonald, J12, Chicago, Ill.

Application April 25, 1941, Serial No. 390,406

12 Claims.

The present invention relates to a control system for a radio set, and more particularly to an improved system by which certain functions of a radio receiving set, such as muting, tuning and control of the volume of'sound emitted from the loud speaker of the set, may be controlled in a simpler and more expeditious manner.

The present invention is particularly useful in connection with radio receivers mounted in motor vehicles, although it has general application wherever it is desired to control aplurality of functions of a radio receiver. The conventional hand tuning or actuation by hand of station selectors with conventional automobile radio receiver installation constitutes a serious hazard, as the drivers attention is distracted and serious accidents have frequently resulted. Furthermore, it is many times important to mute the radio re-- ceiver for short periods of time in order to be able to listen for warning bells at railroad crossings or for the sounds of approaching vehicles or trains. In addition, it is many times desired to change the volume of sound emitted from the loud speaker of the radio receiver, and in accordancewith the present invention this function may. be

controlled by means in combination with the muting and tuning means without distracting the drivers attention.

In accordance with the present invention, mut-r-- ing of the radio receiver, the selection of the desired signal to be received, and control of sound volume from the receiver can be accomplished through a single member actuated, for example,

by foot control with a special type of switch mounted on the floor board of an automobile.

This enables the control operations of the radio receiver, which ordinarily require close attention by the driver, to be carried out without requiring the driver to look at the radio set or remove either 9 hand from the steering Wheel.

Another aspect of the invention also provides a multiple circuit switch for controlling a plurality of circuits which embodies novel features of construction which. permit manufacture of its parts from low cost readily formed materials, and

which also facilitate assembly of the parts.

The embodiment of the switch selected for illustrating this aspect of the invention is designed so it may control two electrical circuits by inter- I dicated to the sense of touch of a person operating the switch. As the switch operator returns from its fully operated position to its normal position, the circuit last to be closed is opened first, the point where the second circuit has opened and the first circuit is about to be opened again being indicated to the sense of touch. Upon completion of movement of the switch operator to the normal position, both circuits are opened. This design also makes it possible for the first circuit to be closed and thereafter opened without disturbing the second circuit which remains open under such circumstances. This design also embodies a contact spring of great durability and a contact arrangement which is not affected by excessive operating pressures. And, moreover, this design readily lends itself to use in combination with a volume control or other type of rheostat operable by the operating member of the switch. It will be understood that a switch having the novel structural features to be disclosed herein may be designed to accommodate a variety of circuit controlling contact arrangements.

The primary object of the present invention is to provide a novel control system for a radio receiving set.

Another object of the present invention is to provide a novel safety control system for an automobile radio receiving set.

Another object of the invention is to provide a novel device for muting or changing the volume of sound emitted by a radio receiver or selecting a desired signal, or performing these functions simultaneously.

Another object of the invention is to provide a novel device for muting a radio receiver, selecting a desired signal, or changing the volume of sound emitted by the loud speaker.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, both as to its organization and manner of operation, to gether with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

Figure 1 is an elevational view partly in section of a switch useful in connection with the invention, the section being taken on line l| of Fig. 2.

Figure 2 is a view'in plan of the switch of Figure 1.

Figure 3 is a view in plan of a portion of the switch of Figure 1.

Figure 4 is a diagrammatic representation of a by .reference character I l. diagrammatically as being located exteriorly of system in which such a switch maybe used in accordance with the invention.

Figure 5 is an exploded view showing the parts partially sectioned on line l-i of Figure 2.

Figure 6 is an elevaticnal View, partly in section, of a modification of the switch of Figure 1.

Figure '7 is a view in plan of a portion of the switch of Figure 6.

Figure 8 is a diagrammatic representation of a system in which the-switch ofFig'ure 6 may be used.

Figure 9 is a diagrammatic representation similar to Figure 8 of a modified system.

The operation of the switch of this invention,

shown in Figures 1 to 3 and 5 of the drawings.

will be described in connection with the control ator to move the movable contact 29. Depressing the operating button 31 of the switch l2 causes 'fiCQl'ltEtCt 29 to engage contact 28 grounding concircuits of a muting and tuning device for a" radio receiver. that the switch of this invention may be used for general circuit control purposes.

Referring to the drawings in detail and tor the present to Figures 3 and 4 thereof, reference numeral 1-9 indicates tunable radio apparatus such as a radio receiver having a solenoid operated station selecting device indicated generally This device is shown the receiver It for the sake of convenience of illustration. The switch of this invention, to be described in detail hereinafter, .is indicated by reference character [2 and is operatively connected to the device II by a shielded cable [4. The device H comprises a shaft l'l operatively connected to -a ratchet gear l 8. The shaft I'I carries or is otherwise connected to a plurality of switches (not shown) which connect previously tuned sets of cooperating circuit elements in the tunable circuits of the receiverso as to obtain automatic tuning of a plurality of preset stations. The operative connection to the tuning switches within the receiver Ill is indicated by the shaft 17 and may be obtained by mounting the switches on this shaft as suggested above, or in any other suitable mannergsuch as by means of gears, belt drives, etc. It'will be understood that any type of electrically operated tuning device may be' operated by the switch l2. One type of such device is shown in .Patent 2,216,671, granted to Eugene F. McDonald, Jr., and dated October 1, 1940. This patent may be referred to for further details of a system of radio control in which a switch of this invention may be used to obtain the advantages pointed outherein.

The electrical connections of the tuning and muting system will now be described briefly before proceeding to a detailed description of the switch l2. The powersupply may comprise a vehicle battery 19 which is connected to the receiver by way of a receiver power switch 2!. The receiver is provided with a speaker 23 operated by a voice coil 24 supplied by the output of the -receiver.ahd having one terminal connected to ground at 2! Conductor .21 of the cable l4 connects the other terminal of the voice coil 2 to a contact 28 of theswitch l2. The switch I2 is preferably mounted on the floor-board of the vehicle in which the system is installed or upon some part of the vehicle easily reached by the occupant thereof. The movable contact 29 of the switch is electrically connected to the grounded base plate through members 59, 6.5, 51, i l and '3]. The base plate- 35 and hence the switch casing is connected to ground at .30 by way of the -metallic sheath SI of the cable M,

It will be understood, however,

"between the sheets '41 and 48.

'tallization and breakage.

.ductor 27 to short circuit the voice coil of the speaker through ground. This serves to mute the speaker. A further depression of the operating button 131 of the switch completes the circuit through the solenoid from ground at 38 by way of the cable sheath 3|, the contacts 29, 28

.and 133, the conductor 36 and thebattery 19.

The solenoid 34 has-a core 38 .to'whichis pivotally connected, as at 139, apawl 4|. A pawl spring iz biases the pawl into engagement with the teeth on the ratchet wheel [8. When the circuit through the solenoid is completed, the core is retracted to .rotate the ratchet 18 .in the direction indicated. After the solenoidjhas rotated the ratchetnto tune in a transmitting sta- 'tion,'which occurs almost immediately, the switch button may be released and the solenoid core will be returned toits original position by means of a spring 44.

The switch [2 the parts of which are shown in section by Figure lot the drawings, and disassembled in Figure 5, includes a base plate 35 .to which is secured by tubular rivets 51 a waferlike contact assembly 46 comprising sheets of insulating material ll and 48 secured together also by rivets-5|. The previously described con- .tact member 33 is secured on a protuberant portion 52 of a metallic strip 53 which is retained Ear 5 5 on the strip 53 provides a terminal to which the conductor 36 may be integrally secured in a permanently conductive manner by soldering or welding. The contact 28 is secured on a resilient member such as a spiral spring 56 which is secured to the insulating sheet 4'! by eyelets El.

inherently long life in use. Since the spring 56 is free of abrupt bends, and since its resilience does not depend on its being bent at any one point between its ends, it is not subject to crys- An upturned portion 58 provides a terminal connectionfor integrally receiving the conductor 21 in good electrical contact.

The cup-shaped contact enclosing member 59 apertured for connection to the base plate 45 by eyelet connections Si or other suitable means.

The eyelet connections shown po sess the advantage of receiving bolts, screws or other connecting means forsecuring the switch 52 to the floor .to accommodate the insulated conductors 2] and 3,5. A guide bushing 63 01 insulating material .is crimped to an aperture Bil located substantially concentrically with respect to the contacts 28 Guild.

The guide bushing 63 serves a threefold purpose in that it provides an insulating holds the spring 66 partly compressed.

The spring 66 presents two substantially flat ends, one of which rests on top of the member 59and the other of which reacts against a washer 6'! which surrounds the reduced portion 68 of the circular body of the contact 29. The washer 61 is seated in the shoulder 69 of the contact 29. The washer 8'! preferably has an outside diam- .eter such that it fits slidably in the cylindrical housing 1i] which has an inwardly turned flange H providing a restricted portion indicated by the reference character 12 which serves to limit outward movement of the washer 61 and thereby It will be seen from this that the movable contact 29 is guided for longitudinal movement without assistance from the aperture F3 in the housing Ill.

At the end of the housing opposite the flange H is an outwardly turned flange 14 by means of which the housing i fastened by welding or other suitable means to the top of the contact enclosure member 55. Above the washer M is a cylindrical sleeve l5. This sleeve is surrounded by another spring H, which is lighter than the spring 66, and the whole is enclosed by the operating button 3'! which is riveted onto the top of the contact 29 at Hi. The operating button 37 overlaps the housing iii to prevent dirt and foreign matter from entering the switch body. In this manner the spring 11 is somewhat compressed under ordinary conditions. The aperture 73 in the housing is: is large enough to accommodate the spring Tl. operating button 31 to move the contact 29 toward circuit closing engagement with the contact 28, the spring E1 is compressed until the inner surface of the button 3'! engages the top of the sleeve l6. At this time, the contact 29 is in full circuit closing engagement with the contact 28. This completes a circuit. In Figure 4, the circuit is completed from the speaker voice coil to ground in the manner explained above by grounding the conductor 21, thereby muting the speaker. At this point, the contact has not yet engaged the contact Further movement of the operating button 3! must necessarily cause compression of the spring #36 since there is now a direct connection between the button 37, the sleeve it and the washer $1. The added resistance of the heavier spring 65 enables the operator to sense the point at which the circuit of conductor 2'! has been closed and the closing of the circuit of conductor 36 is about to occur. Upon additional movement of the contact 29, the contact 28, which i now grounded by the contact 29, engages the contact 33 to complete the circuit to be controlled. which includes conductor 35. In Figure 3, this circuit is completed through the solenoid 34 and serves to change stations.

In operation of the switch, it will be noted that the alignment of the contacts 29, 28 and 33 by reason of their concentric arrangement, prevents damage or misalignment thereof by excessively heavy pressures exerted on the operating button 31. With the button 3'! fully depressed, the thrust of contact 2.9 is taken by the contact 28 which solidly in contact with the fixed contact 33. The spiral spring 55, therefore, is not called upon to resist any of the excess pressure which may be exerted on the operating button, but it is fully effective to maintain the concentric location of the contact 23. Any force tending to displace the contact 28 laterally Upon exertion of pressure on the prevented by the resistance to bending of the spring in the direction of its greatest dimension in cross section. In this respect, the spring may be regarded as a beam curved to spiral shape.

Figure 5 of the drawings serves to show the simple nature of the switch parts and the ease with which they may be assembled. While the manner of assembling the parts of the switch i2 is believed to be apparent from the foregoing, a suggested mode of assembly will be briefly described. The contact spring 56 is secured to insulating sheet 41, and this and insulating sheet 38 are assembled as a unit 48 together with the contact support 53 to which contact 33 has already been secured. This unit is fastened together and secured to the base 45 by means of the rivets 5!.

The insulating guide bushing 63 may be formed into position over the aperture 84 in the contact enclosing member 59, following which the parts carried by the member 59 may be assembled to it by slipping the washer 6'! over the reduced part 68 of the contact member 25 until it rests against the shoulder 89. The contact 29 with the washer 6? in place is inserted upwardly through the aperture '13 in the housing Hi. The sleeve 16 and the spring ll may then he slipped into place to surround the reduced contact portion 68. The operating button 3'! is then riveted in place as indicated by the reference character 78. The spring (56 may now be placed on the member 59 in a position determined by the bushing 63. The housing is may now be secured to the contact enclosing member 59 by welding the flange 74 thereto. Assembly of the switch is completed by crimping the fastening means 6! on the base 45 to the contact enclosure 59 as shown in Figure 1.

Assembly of the switch l2 may be carried out in other ways to suit particular manufacturing methods and assembling machinery if used. The foregoing description of a suggested mode of assembly is illustrative only of the ease with which the switch of this invention may be assembled.

Figures 6 and 7 of the drawings disclose a modified and multiple circuit controlling switch in accordance with the present invention. In this case, a combined circuit controlling switch 84, which is a modification of the switch l2 of Figures 1 to 3 and 5, provides for reducing the volume of sound as well as for muting and tuning the receiver.

Figure 8 of the drawings discloses a modified system in which the switch of Figures 6 and '7 is useful, and similar reference characters are used to designate the same elements as in Figures 3 and 4. The receiver It], the station selecting device I l and the accessory equipment for the receiver are substantially like those illustrated in Figure 4 of the drawings. The combined multiple circuit controlling switch 8L the parts of which are shown in section by Figure 5 of the drawings, is similar in structure to the switch l2 of Figures 1. to 3 and 5 of the drawings, and is preferably mounted on the floor board of the vehicle in which the system is installed so as to be in a position for convenient operation by the foot of the driver of the vehicle, or it may be installed upon some part of the vehicle easily reached by another occupant thereof. The switch 8! is o-peratively connected to the device H by a shielded cable 82 which encloses the conductors 83 and 84. The conductors 83 and 8-! correspond to the conductors 21 and 36 of Figures 3 and 4 of the drawings. The conductor 33 of the cable 82 connects the ungrounded terminal of the speaker voice coil 24 to the contact 85 of .the switch I2. The conductor 84 is connected to one terminal of the solenoid 3- and to the contact 86 of the witch SI. The other terminal of the solenoid, which is the same as the solenoi 3 of Figure 4, is connected to one terminal of the battery I9 through the receiver power switch 2|. The conductor 83 also provides a connection to the volume control section 87 of the circuit controlling switch SI from the voice coil 24 of the speaker. The operating connection between the solenoid core 38 and the ratchet wheel I8, constituting parts of the device II, is the same as that shown in Figure 4 of the drawings.

The switch contact 85 is carried by a spiral spring member 88 and the contact 86 is secured upon a contact supporting strip 89. A waferlike contact assembly SDI, comprising sheets of insulating material 92 and 93, is secured to the base plate 9 of the switch by tubular rivets or other suitable fastening means 96. The rivets 95 also serve to secure the sheets 92 and 93 together so as to retain the contact strip 83 in position between them. The contact strip 89 is provided with a protuberant portion 97, which is apertured as indicated by reference character 98. The previously mentioned contact 86 is secured on the protuberance ill. An car 99 on the strip 89 provides a terminal to which the conductor 8d may be integrally secured in a permanently conductive manner as by soldering or welding. The contact 85 is secured on the apertured portion IOI of the spiral spring member 83. The spiral spring member 88 is fastened to the insulating sheet 92 by suitable fastening means such as the eyelets W2. An upturned portion IQ? of the spring 88 provides a terminal connection for integrally receiving the conductor 83 in good electrical contact.

The cup-shaped contact enclosing member IE4 is adapted for connection to the base plate 94 by eyelet connections IE6 or other suitable securing means. A series of notches located in the same position as the notches 62 in Figure 2 of the drawings may be provided in the annular wall of the contact enclosing member IM to accommodate the insulated conductors 83 and 84. The reciprocable and rotatable contact It? is guided for longitudinal movement by a guide bushing I08 of insulating material which is crimped to an aperture located substantially concentrically with the apertures in the contact supporting members 83 and 89. The guide bushing I138 performs substantially the same functions as the bushing 63 shown in Figures 1 and 5 of the drawings. A disk or washer I99 surrounds the reduced portion III of th circular body of the contact H31 and is seated on the shoulder H2. A spring II l presents two substantially flat ends, one of which rests on the member IM, and the other reacts against the washer I89. The washer IE9 fits slidably in a cylindrical housing IIE which has an inwardly turned flange II'I providing a restricted portion indicated at I I8. Outward movement of the Washer IE9 is limited by the restricted portion I it to thereby hold the spring II partly compressed. The housing III may be secured to the top of the contact enclosure member I04 by welding its outwardly turned flange M9 to the enclosure member. A cylindrical sleeve I2I surrounds the reduced portion I I I of the contact I81 and rests on the washer I39. This sleeve is surrounded by another spring I23 which is lighter single member.

than the spring II 4. The aperture provided at the top of th housing I I6 is large enough to accommodate the spring I 23. The combined operating knob and button I2 3, comprising the capshaped member I25 and the annular member I27, is riveted on to the top of the contact member ItII as indicated by reference character I28. The annular member I2! is knurled or otherwise formed to provide a roughened surface as indicated by reference character I29, so that it may be rotated by the foot of the person desiring to control the volume of sound emitted by the loud speaker of the radio receiver I0. The cap-shaped member I25 overlaps the housing H6 to prevent dirt and foreign matter from entering the switch. After the connection I28 is made the spring I23 is held in compression between the combined knob and button I24 and the washer I09. The portion of the contact IIFI which provides the permanent connection I28 is preferably square in cross section to fit a square aperture in the cap member I25, thereby to insure rotation of the contact IIII when the combined operating knob and button is rotated. It will be understood that any irregular shape may be provided for the permanent connection I28 at the top of contact Ill! where .contact It? is connected to the annular member I21 to insure that the contact I [I1 shall always rotate with the annular member I21, the combined operating member I25 thereby being essentially a The switch casing is connected to ground at I30 (Figures '7 and 8) by way of the metallic sheath I3I of the cable 82. The point of connection to ground I3!) is, like the point 30 of Figure 4, preferably some metallic portion of the device to which the cable 82 is connected. In Figure 8 the ground connection may be made directly to the external casing of the receiver ID. The movable contact I81 of the switch 8I is electrically connected to the grounded base plate 94 through the members IM, II I, I69, I23 and I25.

The combined operating knob and button I24 is operated in the same manner as the operating button 31 of the switch I2 of Figure 1 to mute and tune the receiver. Upon exertion of pressure on the combined operating knob and button I24 to reciprocate the contact IE3? toward circuit closing engagement with the contact 85, the top of the sleeve I2I is engaged by the inner, or lower,

surface of the combined knob and button following initial compression of the spring I23.

At this time the contact IiJI is in full circuit closing engagement with the contact 85, completing a circuit from the speaker voice coil to ground by grounding the conductor 83 and thereby muting the speaker. At this point in its movement, the contact Iii? has not brought the contact into circuit closing engagement with the contact 86. Further movement of the combined knob and operating button I24 causes the spring I M to be compressed since there is now a direct connection between the knob and operating button I24, the sleeve I2I and the washer I09. Because of the added resistance of the spring I I 4, the operator can sense the point at which the circuit of conductor 83 has been closed and the closing of the circuit of conductor 84 is about to occur. Additional movement of the contact It? will cause the contact 85, which is now grounded by the contact I01, to engage the contact 83 to complete the circuit including the conductor 84.

The volume control section 37 of the combined switch SI includes a volume control rheostat I32 which may be of any well known type, adjustable by rotating its operating shaft I 33. The rheostat I32 is shown as being secured to a bracket I34 by means of a nut I36. The supporting means for the rheostat just described is convenient since volume control rheostats are readily available which are of the panel mounted type shown, employing the nut I36. However, it will be understood that any type of rheostat may be mounted in any desired manner on the switch 8| with its operating shaft projecting upwardly into the body of the switch as shown in Figure 6 of the drawings, or the combination of a switch and volume control may be eifected in other ways. To prevent ingress of foreign matter into the volume control section 81 and the contacts of the switch 81, a cover member I3! is provided which encloses the rheostat I32 and the lower end of the switch.

The operating shaft I33 of the rheostat is slotted or bifurcated as shown at I38 so as to provide an extensible driving connection with a pin at I39 projecting from side to side through a bore MI in the end of the contact I c1. The extensible connection provided between the bifurcated end of the shaft I33 and the pin I39 permay be muted at any time in the manner pointed r out above irrespective of the angular position of the rheostat shaft I233.

The operation of the multiple circuit control system of Figure 8 will now be explained briefly. Muting and tuning is accomplished in the manner already pointed out in connection with the description of the structure of the combined switch 8!. The volume of sound emitted by the loud speaker 23 is controlled by varying the amount of resistance placed in shunt with the loud speaker voice coil 25. That is, the single control member I24 may be moved in one direction from a normal position to a muting position to mute the loud speaker without operating the station changing mechanism and may be further moved in the same direction to operate the station changing mechanism while keeping the set muted, and the same single control member I24 may be moved in a different direction, that is, in rotation, to change the volume of sound coming from the loud speaker. The usual volume control arrangement, indicated by reference character I40, ordinarily forming a part of the receiver, is operated in the normal manner to select a desired volume level, and the volume control rheostat I32 serves to reduce the volume below this level when desired. The volume control arrangement of Figure 8 of the drawings does not interfere with the use of the ordinary volume control, nor does it interfere with the automatic volume control usually supplied with present day receivers- Special shielding or insulation need not be provided for the conductor 83. The arrangement illustrated by Figure 3 of the drawings has the advantage that it does not require any conductors between the combined switch BI and the receiver ID in addition to those shown in Figure 4 of the drawings. It will be understood that the volume control section 81 of the switch 8| may be used to replace the regular volume control of the receiver if suitable precautions are taken to shield the leads between the receiver and the volume control so as to substantially eliminate the possibility of leakage and of picking up stray noises or stray signals.

Figure 9 of the drawings is a diagrammatic showing of a modified radio control system in accordance with this invention in which volume control as well as muting and tuning may be accomplished by the combined switch 81 of Figures 6 and '7 of the drawings. In this figure similar reference characters are used to designate the same elements as are illustrated by Figure 4. The receiver ID, the station selecting device II and the accessory equipment for the receiver may be of any conventional type such as is illustrated in Figure 4. of the drawings. Suitable output terminals on the receiver I3 serve to energize the voice coil 24 of the loud speaker 23. The combined switch Sla, which is similar to the switch ill of Figures 6 and 8, is provided with a volume control potentiometer M4 which has one terminal of its resistor Mt connected to ground at any suitable point in or on the switch casing, or on the sheath I 4? of the shielded cable 545. The remaining terminal of the resistor IE5 is connected to the muting contact 85 of the switch tic preferably by way of a conductor M9 connected to the conductor I5I. The conductor I5! corresponds in function to the conductor 83 of Figure 8 and is connected to one terminal of the voice coil 24 of the loud speaker, the other voice coil terminal being grounded. The conductor I52 connects the station changing contact of switch 8Ia to the solenoid 313 which performs the same function as the solenoid 33 of Figure 4 of the drawings. A contact ltd, slidable on the resistor I46, is connected to the cathode I55 of an amplifier tube I5! in the radio receiver it) by way of a conductor I58. This tube 15? is preferably one of the audio amplifier tubes. The volume control arrangement just described does not interfere with the use of the regular volume control I59, nor does it interfere with the automatic volume control arrangement if one is provided in the receiver. The volume control arrangement just described operates by including some of the voltage appearing across the voice coil 24 in series with the cathode circuit of an audio amplifier tube. The phase relationship of the voltage applied to the amplifier tube cathode is such that a reduction in gain results. Since the signal voltage fed into the audio amplifier depends on the setting of the regular volume control 59 of the receiver, the auxiliary inverse feed back volume control of Figure 9 gives a variation in audio output below the level established by the main volume control. The value of the resistor I43 is not critical and may, for standard receivers of present day design, be in the neighborhood of 500 ohms. The system of Figure 9 has the advantage of not requiring high impedance circuits externally of the receiver which would pick up undesirable noises or be affected by insulation leakage. The relatively low impedance circuit, including the resistor I46 and the sliding contact I54, have substantially no tendency to pick up extraneous signals or noises generated by the vehicle engine.

A plurality of switches, such as those shown in Figures 1 and 6, may be employed so that the receiver may be controlled from more than one point. The system of the present invention makes possible station changing, control of soundvolume andmuting of the radio set by a single foot-operated'control device without the operator having to look at the set, or dial, or remove his hands from the automobile controls. The system of the present invention is particularly applicable to the control of automobile radio sets and has been described in detail with respect to operation from low voltage batteries. However, other types of radio sets, such assets operated from alternating current or higher voltage direct current, may be operated from a remote point in accordance with the principles of the present invention. The invention has been illustrated in connection with an electrical type of automatic tuning wherein individual presettable condensers or inductances are employed, but is also applicable to other types of automatic tuning arrangement.

This application is a continuation in part of my co-pending application Serial No. 359,137, filed September 30, 1940, now Patent No. 2,307,329, granted January 5, 1943.

While there is shown and described herean illustrative embodiment of the invention, the invention may be embodied in other forms, and therefore, the invention is not limited except as indicated by the terms and scope of the appended claims.

What is claimed is:

1. An automobile radio receiving system comprising a receiving set having a plurality of presettable means for presetting said set to receive a signal from any one of a plurality of transmitting stations, selecting means for selecting a desired one of said presettable means, muting means for said set, volume control means for said set, and control means for said selecting means, said muting means and said volume control means including a foot control device positioned at the floor board of said automobile, to be actuated by the driver of said automobile, said control means providing independent operation of said volume control means and muting means, an electrical connection from said receiving set to said foot control device for operating said selecting means upon actuation of said device, and a single electrical connection from said receiving set to said device to provide for operation of said volume control and said muting means upon actuation of said device.

2. An automobile radio receiving system comprising a receiving set having a station changing mechanism, a muting means for said set, a volume controlling means for said set, and a single control member actuatable inone direction from a normal position to a mutingposition for operating said muting means to mute said set independently of said station changing mechanism and volume controlling means and further actuatable in the same direction to a station changing position for operating said station changing mechanism to change the station being received while maintaining said set muted, said volume controlling means being operable independently of said station changing mechanism and said muting means by movement of said member in another direction.

3. An automobile radio receiving system comprising a receiving set having a station changing mechanism, a muting means for'said set, a volume controlling means for said set, and a single control member actuatable in one direction from a normal position to a muting position for operating said muting means. to mute said set independently of said station changing mechanism and volume controlling means and further actuatable in the same direction to a station changing position for operating said'station changing mechanism to change the station being received while maintaining said set muted, said volume controlling means being operable independently of said station changing mechanism and said muting means by movement of said member in another direction, one of-said directions of movement of said-member being a rotational movement;

4. An automobile radio receiving system comprising a receiving set having a step by step station changing mechanism, a muting means for said set, a volume controlling means for said set, and a single control member actuata'ble in one direction from a normal position to a mutin position for operating said'muting means to mute said set independently of said station changing mechanism and further actuatable in the same direction to operate said station changing mechanism while maintainin said set muted, said volume controlling means being operable independently of said station changing mechanism and said muting means by movement of said member in a plane at right angles to said direction of movement.

5. An automobile radio receiving system comprising a receiving set having a station changing mechanism, a muting means forsaid set, a volume controlling means for said set' and a single control means reciprocable in one direction from a normal position to a muting position for operating said muting means to mute said set independently of said station changing mechanism and volume controlling means and further recipro-cable in the same direction to a station changing position for operating said station changing mechanism to change the station being received while maintaining said set muted, said volume controlling mean being operable independently of said station changing mechanism and said muting means by movement of said control means in a plane at right angles to the direction of saidreciprocation.

6. An automobile radio receiving system comprising a receiving set having a station changing mechanism, a muting means for said set, a volume controlling means for said set and a single control means reciprocable in one direction from a normal position to a muting position for operating said muting means to mute saidset independently of said station changing mechanism and volume controlling means and further reciprocable in the same direction to a station changing position for operating said station changing mechanism to change the station being received while maintaining said set muted, said volume controlling means being operable independently of said station changing mechanism and said muting means by rotational movement of said control means.

7. An automobile radio receiving system comprising a receiving set having a step by step station changing mechanism, a solenoid, asource of electric power and a circuit associated therewith having a normally open contact for energizing said solenoid to step said station changing -mech-' anism upon closing'of said contact,- a muting means for said set including a muting circuit having a second normally open contact, a volume controlling means for said set, and a single con trol member actuatable in one direction from a normal position to a mutin position for closing said second contact to mute said set independently of said station changing mechanism and ume controllin means for said set, a single con trol member actuatable in one direction from a normal position to a mutin position for operating said muting means to mute said set independently of said station changin mechanism and volume controlling means and further actuatable in the same direction to a station changing position for operating said station changing mechanism to change the station being received while maintaining said set muted, said volume controlling means being operable independently of said station changing mechanism and said muting means by movement of said member in another direction and resilient mean for resisting movement of said control member from said normal position to said muting position and resisting movement of said control member from said muting position to said station changing position with abruptl increased force over the resisting force from said normal position to said muting position.

9. An automobile radio receiving system comprising a receiving set having a step by step station changing mechanism, a muting means for said set, a volume controlling means for said set, and a single control member actuatable in one direction from a normal position to a muting position for operating said muting means to mute said set independently of said station changing mechanism and further actuatable'in the same direction to step said station changing mechanism while maintainin said set muted, said volume controlling means being operable independently of said station changing mechanism and said muting means by movement of said member in another direction, said control member being a foot control device positioned adjacent the floorboard of said automobile to be operated by the foot of the driver of said automobile.

10. An automobile radio receiving system comprising a receiving set having step-by-step station changing mechanism, a solenoid, a source of electric power and a circuit associated therewith havin a normally open contact arranged when closed to energize said solenoid to step said station changing mechanism. a muting means for said set including a muting circuit having a second normally open contact, a volume controlling means for said set, and a foot controlled device positioned adjacent the iioorboard of said automobile to be operated by the foot of the driver of said automobile, said foot control device comprising a single control member movable upon pressure by the foot of said driver to move from a normal position to a muting position for closing the second contact to mut said set independently of said station changin mechanism and volume controlling means and further movable in the same direction upon further pressure by the foot of said driver to close said first mentioned contact to step said station changing mechanism while maintaining said second contact closed, said volume controlling means being operable independently of said station changing mechanism and said muting means by rotation of said single control member by the foot of said driver.

11. An automobile radio receiving system comprising a receiving set having a step-by-step station changing mechanism, a solenoid, a source of electric power and a circuit associated therewith having a normally open contact arranged when closed to energize said solenoid to step said station changing mechanism, a muting means for said set including a muting circuit having a second normally open contact, a volume controlling means for said set, a single control member actuable in one direction from a normal position to a muting position for closing said second contact to mute said set independently of said station changing mechanism and volume controlling means and further actuable in the same direction to close said first mentioned contact to step said station changing mechanism while maintaining said second contact closed, said volume controlling means being operable independently of said station changing mechanism and said muting means by movement of said control member in another direction, and resilient means for resisting movement of said control member from said normal position to said mutin position and for resisting movement of said control member from said muting position to said station changing position with abruptly increased force over the resisting force from said normal position to said muting position.

12. An automobile radio receiving system comprising a receiving set having step-by-step station changing mechanism, a solenoid, a source of electric power and a circuit associated therewith having a normally open contact arranged when closed to energize said solenoid to step said station changing mechanism, a muting means including a muting circuit having a second normally open contact, a volume controllin means for said set, a foot control device positioned adjacent the floorboard of said automobile to be operated by the foot of the driver of said automobile, said foot control device comprising a single control member movable upon pressure by the foot of said driver in one direction from a normal position to a muting position for closing said second contact to mute said set independently of said station changing mechanism and volume controlling means and further movable in the same direction upon further pressure of said driver to close said first mentioned contact to step said station changin mechanism while maintaining said second contact closed, said volume controlling means being operable independently of said station changing mechanism and said muting means by rotation of said control member by the foot of said driver, and resilient means for resisting movement of said control member by the foot of said driver from said normal position to said muting position and for resisting movement of said control member by the foot of said driver from said muting position to said station changing position with abruptly increased force sensible to said driver over the resisting force from said normal position to said muting position.

EUGENE F. MCDONALD, JR. 

